1. Field of the Invention
This invention relates to the art of magnetic recording and reproducing system and more particularly, to magnetic recording media for use in such systems.
2. Description of the Prior Art
In order to impart high durability and good travelling performance to magnetic recording media, it is the usual practice that the magnetic recording layer formed on bases or substrates is made of a magnetic recording composition which comprises a magnetic powder and abrasive particles dispersed in thermosetting polymer binders. The abrasive particles used for these purposes are usually made of inorganic materials such as alumina and have a size of about 0.5 .mu.m in a minimum. When such large-size particles are dispersed in thermosetting polymer binders and the dispersion applied onto substrates is thermally cured, a high strength recording layer is not obtained because of the rather poor affinity of the inorganic particles for the thermosetting polymer binder and the large size of the particles. Accordingly, satisfactorily high durability of the recording layer cannot always be obtained.
Magnetic discs of the type which is used in magnetic disc apparatus and, particular, Winchester-type magnetic disc apparatus in which the magnetic head is in contact with a magnetic disc surface when the apparatus is not operated and the magnetic head is lifted out of the disc surface when the disc is rotated at high speed should have good mechanical characteristics of the film layer such as high abrasive resistance, high impact resistance and the like.